I continued along the Middle Causeway to the junction of Long Pond, Humphries and Vermet Units where I decided to walk the bike for fear of spooking any shorebirds that might be in the mudflats east of the sunflower field. Up ahead I could see a Snowy Egret among a flock of Mallard and several Canada Geese (w/ goslings). I also saw a van along the east dike that I suspected belonged to Adam Byrne, so I called him, only to find out that he and Scott Terry had seen the ibis earlier this morning in the same area. They ID'd the birds as White-faced Ibis and a possible hybrid. I told him that the birds were in the area, having watched them fly this way from the Lautenschager Unit. It wasn't until I hung up the the phone and walked another 30 yds. that I saw two dark forms near the egret that I knew immediately must be the ibis.
The second bird is a bit more curious and worthy of closer inspection. It also appears to be an adult in alternate plumage as evidenced by the scarlet/brown head and neck. A non-breeding adult would show paler brown feathering with white fleks. Its bill is gray, and legs show a pinkish coloration that also suggest White-faced Ibis. Legs appeared slightly darker than the former bird, but note that leg coloration is variable in Plegadis ibis and not a good indicator for species separation.
Immediately evident is the lack of white feathering surrounding a pink loral skin that covers the face. The eyes on this bird also appeared darker than expected for an alternate-plumaged adult WFIB (not bright red). Dark eyes are a trait of Glossy Ibis, so the evidence is here supporting a hybrid White-faced x Glossy Ibis. And, while I fully agree with anyone suggesting that this bird is indeed a hybrid (and should stop here), I've done just enough research to ask a question or two: Sibley (2000) described in his book a bright vs. drab adult, with this individual looking much like the drab adult. Is it possible for a breeding-plumaged adult WFIB not to have a 'high-breeding' appearance? Can hormone deficiencies affect this bird enough to make it appear as a hybrid? This bird shows evidence of slight white feathering (initiating?) along the forehead.
On a Glossy Ibis the loral skin tends to be bluer/grayer, and any white bordering the eye tends to disappear behind the eye. On this bird the loral skin has a pink coloration and there is evidence of skin behind the eye, but I don't know if this is significant of either species. Although dark, the eyes do show evidence of red. Are they red enough? Of course, it probably doesn't matter whether this bird is a pure WFIB or a hybrid, but we can, at least, raise some questions for those more-experienced to address... Arterburn and Grzybowski (2003) published an interesting article in American Birds regarding hybridization in Plegadis ibis.
I left the guys and headed out to Cell 3, where they had earlier seen 4 White-rumped Sandpipers along w/ Semipalmated Plovers and Sandpipers, and Dunlin. My visit yielded only a dozen or so Dunlin and the Semi's far across the mudflats along the east side of Cell 3. I only stayed a few minutes to scan the flats, and to scan the scan the Humphries Unit for Cattle Egrets (3 in the trees among numerous Black-crowned Night Herons).
From there a ride along the east shore of the Vermet Unit yielded only the usual Great Egrets, Tree Swallows, BCNH, Common Moorhens and American Coots. I stopped along the North Causeway long enough to digiscope some near-shore Lesser Scaup among several Redhead ducks (nice to see this late in the spring).
Just before heading back along the west side of the Vermet Unit I took a few minutes to photograph fly-by Forster's Terns foraging/diving along the north shoreline. They are gorgeous!
While driving back north along US-Turnpike Rd. I spotted a Cattle Egret foraging in the grass next to the pond at the corner of Roberts Rd. I pulled off to the side of the road and digiscoped the 'high-breeding' adult bird (red bill and feet) while it foraged in the grass. I put together this composite image showing how far back it bobs its head while walking!
Kaufman, Kenn, Kaufman Field Guide to Advanced Birding, 2011, Houghton Mifflin Harcourt, New York.
Sibley, David Allen, The Sibley Guide to Birds, National Audubon Society, 2000, Alfred A. Knopf, New York.
Arterburn, James W., and Grzybowski, Joseph A., Hybridization Between Glossy and White-faced Ibises, 2003, North American Birds, Vol. 57, No. 1, pp. 136-139.